Fix Bug 778063, ensure all pages validates against w3c validator

@rhelmer r?

So this actually fixes:
https://bugzilla.mozilla.org/show_bug.cgi?id=788063
https://bugzilla.mozilla.org/show_bug.cgi?id=682888
https://bugzilla.mozilla.org/show_bug.cgi?id=794149

Most of these are validated using the web developer page's Validate local HTML but, for pages like Crash Trends and report.index, one needs to use the generated HTML function of the Web Developer toolbar and then use the w3's direct input validator setting the DOCTYPE to HTML5.

If I missed anything, just let me know.